This paper used rock-capillary model to simulate the formation pore volume,and derives the variation equation between paraffin precipitation and formation parameters using the correlation among surface area to volume ratio,porosity and permeability,etc.

Based on the existence of the chemical phases of Zn_3(PO_4)_2·4H_2O,area integrals or intensities of the Zn_3(PO_4)_2·4H_2O phase from the faces of(020)and(241)are obtained and face ratio of phosphide tunica of the samples can be calculated.

Compactness Analysis of Gasoline Engine Combustion Chamber by Surface to Surface Ratio;

The effect of confluence angle, discharge ratio (ratio of branch pipe discharge to total discharge in main pipe) and area ratio (ratio of branch pipe area to main pipe area) were analyzed.

By using the semi experiential engineering arithmetic based on the ideology of area ratio, the slope of lift coefficient curve, the zero lift drag coefficient and the induced drag factor of double delta wing aircraft were calculated.

The phase state,chemical structure,surface morphology,specific surface areas and mesoporous structure of the synthesized silica- based xerogels were measured systemically by means of X-ray diffraction(XRD),infrared spectrum (FTIR),transmission electron microscope(TEM),and N_2 adsoption-desoption(BET)techniques,re- spectively.

Catalyst activity was determined by not only specific surface area of catalyst but also the distributions of active center and utilization ratio of internal surface.

A method for measuring the specific surface area and pore volume of ion-exchange resin by N_2 absorption apparatus is introduced.